KR20130035887A - High frequency power supply device - Google Patents

Abstract

PURPOSE: A high frequency power supply device is provided to prevent a change generation in the mean value of high frequency power in case a high frequency power is supplied as a load in a different high frequency power supply device and prevent the degradation of an output control through the performance of the output control for evenly maintaining the mean value of high frequency power. CONSTITUTION: A high frequency power supply device includes a high frequency power generating unit(4) comprised in order to output a high frequency power for supplying to a load; a high frequency power detecting unit(801) detecting the mean value of high frequency power which is a control object in the output side of the high frequency power generating unit; an activation amount calculating unit(802) comprised in order to calculate an activation amount for maintaining the detected mean value of high frequency power in a set value; and a control part(8) including a control signal output unit(803) comprised in order to output a control signal given to the high frequency power generating unit. [Reference numerals] (1) Commercial power supply; (10) Power change period detecting unit; (11) Control period setting means; (2) DC power supply unit; (20) Different frequency power supply source; (201) Rectifier circuit; (202) Inverter; (203) Rectifier and smoothing circuit; (3) High frequency power amplifying unit; (4) High frequency power generating unit; (5) Directional coupler; (6) Impedance matching unit; (7) Load; (8) Control part; (801) High frequency power detecting unit; (802) Duty ratio calculating unit(activation amount calculating unit); (803) Control signal output unit; (804) Timing controller; (AA) Power setting value;

Description

[0001] HIGH FREQUENCY POWER SUPPLY DEVICE [0002]

The disclosure, including the specification, drawings and claims of Japanese Patent Application No. 2011-217628 dated September 30, 2011, is hereby incorporated by reference in its entirety.

The present invention relates to a plasma processing apparatus and a plasma processing apparatus which perform thin film formation, surface reformation or thin film removal (etching or ashing) processing using a plasma in a semiconductor or a liquid crystal and a high frequency power Supply device.

For example, as disclosed in Patent Document 1, a high-frequency power supply apparatus for supplying a high-frequency power to a plasma load or the like can control the output by a predetermined operation amount (for example, a duty ratio of PWM control performed by a DC / DC converter) And a control unit for controlling the high-frequency power generating unit and the high-frequency power generating unit, the high-frequency power generating unit having a high-frequency power amplifying unit for generating a high-frequency power to be supplied to the load using the output voltage of the DC power supply unit as a power supply voltage.

The DC power supply section includes, for example, a rectifier circuit (converter) for converting the output of the commercial power supply into a DC output, an inverter for converting the output of the rectifier circuit to an AC voltage, and a rectifying and smoothing circuit for rectifying and smoothing the output of the inverter DC / DC converter.

The high-frequency power amplifier includes a power amplifier for amplifying a high-frequency signal using an output voltage of the DC power supply as a power supply voltage, and an inverter for converting the output of the DC power supply into a high-frequency output. The high frequency power obtained by the high frequency power generating section constituted by the DC power supply section and the high frequency power amplifying section is supplied to a load such as a plasma load through the impedance matching section as necessary.

The control unit for controlling the high-frequency power generation unit detects the level of the high-frequency power at the output side of the high-frequency power generation unit at each detection timing, which is the timing that comes during each setting control period, to obtain the high- A high frequency power detection unit for detecting a moving average value calculated from n detection data detected at n (n is an integer of 2 or more) detection timing as an average value of the subject high frequency power; The magnitude of a variable for determining the level of the high-frequency power output from the high-frequency power generation unit is set as the operation amount of the high-frequency power generation unit, and the average value of the high-frequency power detected by the high- An operation amount calculation unit for calculating an operation amount required for the operation; And a control signal output section for outputting a control signal given to the high-frequency power generation section for each control period in order to take an operation amount of the high-frequency power generation section as the operation amount calculated by the operation amount calculation section.

The operation amount of the high-frequency power generation unit is a variable that determines the output of the DC power supply unit or the gain of the power amplifier constituting the high-frequency power amplification unit 3. [ For example, when the DC power supply unit is constituted by a DC / DC converter having the configuration described above, the duty ratio of the PWM control of the inverter for converting the output of the rectification circuit to the AC voltage may be an operation amount.

In the case of performing the control for maintaining the output of the high-frequency power supply device at the set value, the control for maintaining the level (instantaneous value) of the high-frequency power that is detected during the control period and is the object of the control at the set value is not performed, The control for detecting the average value of the output level of the power supply device and maintaining the average value at the set value is performed. As a method for this, a method of controlling the high-frequency power generation unit detects the level of the high-frequency power to be controlled during each control period and considers the moving average value of the level of the high-frequency power obtained from the latest detection data as the average value of the high- , And is used to maintain this average value at the set value.

In a plasma processing apparatus that performs various kinds of processing using plasma in a workpiece such as a semiconductor or a liquid crystal, plasma is generated by applying a high frequency power between electrodes provided in the processing chamber, and a bias power is applied to the plasma It is necessary to perform various kinds of control such as control of ion energy control and the like in addition to high frequency power for generating plasma due to the necessity of planning the miniaturization and speedup of the process. A high-frequency power supply for supplying a high-frequency power for generating a plasma and a high-frequency power supply for supplying a high-frequency power for a bias have different frequencies. For example, the output frequency of high-frequency power for generating a high-frequency power for generating plasma is in a frequency range adjacent to several tens to several hundreds of MHz, and the output frequency of high-frequency power for generating high- It is in a relatively low frequency range. As shown in Fig. 7, in Patent Document 1, a power supply system for receiving power from the first and second high-frequency power supply devices A and B having different output frequencies to the plasma load C is shown .

The power supply system for supplying the high-frequency power to the load such as the plasma load C can supply the high-frequency power having the non-modulated continuous voltage waveform to the load C, Frequency power having a waveform can be supplied.

Patent Document 1: Japanese Patent Application Publication No. 2009-238516A

In a system in which the first high-frequency power supply device A and the second high-frequency power supply device B are installed to simultaneously supply power to the plasma load C as shown in Fig. 7, frequency f1 = 3.2 MHz) and a substantially constant level of high frequency power at which the voltage V1 forms a continuous waveform (non-modulated waveform) is converted from the first high frequency power supply A to the plasma load C Since the output frequency is f2 (for example, f2 = 60 MHz) and the high frequency power is modulated into a pulse waveform having frequency f3 (for example, f3 is 10 kHz to 90 kHz) 1 / f3 may be supplied to the plasma load C from the second high-frequency power supply B as shown in Fig. 8B. In this case, the fluctuation (low level change of the low frequency) can occur at the average value of the output of the first high-frequency power supply device A that outputs the high-frequency power of the continuous waveform.

In the power supply system shown in Fig. 7, the high frequency power of the continuous waveform (non-modulated waveform) can be supplied to the plasma load C from the first high frequency power supply device A, and the pulse modulated high frequency power is supplied to the second And may be supplied to the plasma load C from the high-frequency power supply device B. [ In this case, when the modulated frequency of the high-frequency power given to the plasma load C changes in the second high-frequency power supply device B, the output control for maintaining the output of the first high- The accuracy of the measurement may be deteriorated.

It is necessary to perform control for maintaining the average value of the high-frequency power supplied to the plasma load at a set value in order to perform fine processing of the semiconductor or the like with high accuracy. Therefore, the high- It is necessary to avoid the deterioration of the accuracy of the change or output control.

7, the high-frequency power supply device according to the present invention generates high-frequency power of a continuous waveform (non-modulated waveform) between a plurality of high-frequency power supply devices that simultaneously supply high-frequency power to the load C Frequency power supply device.

An object of the present invention is to provide a high-frequency power supply apparatus that supplies high-frequency power of a continuous waveform having a constant average value to a load, in which, when high-frequency power modulated by a pulse waveform or the like is supplied to a load from another high- Frequency power is prevented from being fluctuated and the accuracy of the output control is prevented from being deteriorated by performing the output control for keeping the average value of the high-frequency power detected from the output side and being the target of the control constant will be.

The present invention relates to a high-frequency power generation apparatus, comprising a high-frequency power generation unit configured to output a high-frequency power to be supplied to a load, and a high-frequency power generation unit configured to detect an average value of high-frequency power to be controlled at an output side of the high- And a control section configured to control the high-frequency power generation section for the high-frequency power supply section.

In the high-frequency power supply apparatus according to the present invention, the control unit detects the level of the high-frequency power that needs to be the target of detection in order to obtain the high-frequency power to be controlled at the timing that comes to each control period (Tc) The moving average value of the high frequency power to be detected is obtained from the n detection data (n is an integer of 2 or more) obtained at the latest n detection timing, and the moving average value is set as the average value of the high frequency power to be detected, A high frequency power detection unit configured to detect an average value of high frequency electric power to be subjected to the detection; It is necessary to set the magnitude of a variable for determining the level of the high-frequency power output from the high-frequency power generation section as the operation amount of the high-frequency power generation section and to maintain the average value of the high- frequency power detected by the high- An operation amount calculation unit configured to calculate an operation amount of the vehicle; And a control signal output unit configured to output a control signal to be given to the high-frequency power generation unit to an operation amount calculated by the operation amount calculation unit in each control period.

According to the present invention, the power variation period detecting unit is configured to detect the level change of the high-frequency power detected at the output side of the high-frequency power generating unit due to the periodic change of the level of the high-frequency power applied to the load from the other high- And the control period setting unit is configured to set the control period Tc to an appropriate value in accordance with the power change period Tz detected by the power change period detection unit.

According to the present invention, the high frequency power to be controlled can be the active power obtained by subtracting the reflected wave power from the progressive wave power or traveling wave power. The high-frequency power to be detected is determined depending on the high-frequency power to be controlled. When the active power is to be controlled, the progressive wave power and the reflected wave power are to be detected. On the other hand, when the progressive wave power is to be controlled, only the progressive wave power is detected.

If the high frequency power having a continuous waveform is supplied to the load from the high frequency power supply apparatus and the high frequency power whose level is periodically changed due to the modulation of the high frequency power through the pulse waveform or the like is applied to the load from another high frequency power supply apparatus, A periodic level change occurs in the high frequency power detected at the output side of the high frequency power supply device which outputs the high frequency power having the continuous waveform. If the control period does not have an appropriate value according to the level change period (power change period) in the case where a periodic level change occurs in the high-frequency power detected at the output side of the high-frequency power supply device as described above, Frequency power generating device that outputs high-frequency power having a non-modulated waveform). This condition occurs when the difference between the control period and the power change period is a simple difference. In the high-frequency power supply device in the related art, since the control period is set to be constant, the modulation frequency of the high-frequency power supplied to the load from the other high-frequency power supply device is changed so that the high-frequency power detected from the output side of the high- If the value of the control period Tc sometimes approaches the value of the power change period Tz when the period Tz of the rising level change is changed, the fluctuation can occur at the output of the high frequency power generation section.

According to the present invention, the power variation period detecting unit is configured to detect the level change of the high-frequency power detected at the output side of the high-frequency power generating unit due to the periodic change of the level of the high-frequency power applied to the load from the other high- And the control period setting unit is configured to set the control period Tc to an appropriate value in accordance with the detected power change period Tz so that the control period Tc is set to be appropriate for the power change period Tz And the control period and the power variation period are prevented from approaching each other. Therefore, fluctuations are prevented from occurring in the output of the high-frequency power generating apparatus that outputs the high-frequency power having the continuous waveform. In addition, since the control period can be set to reduce the error between the moving average value and the true average value of the high-frequency power detected by the high-frequency power detecting section, the deterioration of the accuracy of the output control can be prevented. In the present description, the "appropriate value" of the control period does not mean a sole value, but rather an average value included within a suitable range where errors between the moving average value and the true average value of the high- it means.

Note that the appropriate value of the control period Tc is a function of the relationship between the number of pieces of data necessary for calculating the arithmetic mean (ns: the number of essential data) and the number of pieces of detection data (n) used for calculating the moving average value (Ns 占 Tc) necessary for obtaining the same number of pieces of detection data as the number of data (ns) necessary for calculating the arithmetic mean value and the time (n 占 Tc) required for obtaining n detection data used for calculating the moving average value ), As shown in FIG.

The number of data (ns: the number of necessary data) required to calculate the arithmetic mean value over the k cycles of the level change of the high-frequency power detected in the power change period Tz in each control period Tc ) Can be obtained by the equation ns = k x {Tz / | m? Tz-Tc |}, where m is an integer of 1 or more and mTz? Tc.

It is necessary to reduce the difference between the moving average value of the high frequency power detected by the high frequency detecting unit and the true average value (arithmetic average value) so as to accurately perform the output control. When the moving average value of the high frequency power is calculated from the n detection data through the detection of the high frequency level at which the level changes in the power variation period Tz, the number of essential data ns calculated by the above described equation becomes the moving average value n = ns) or the difference between n and ns is preferably small in order to reduce the error between the moving average value and the true average value. In addition, in order to reduce the error between the moving average value and the true average value, a difference between the time (n x Tc) necessary for calculating the moving average value and the time required to obtain ns detection data (ns x Tc) is preferable.

As is apparent from the above-described equation, in order to accurately calculate the arithmetic average value of the k-cycle level change of the high-frequency power, it is necessary to obtain about the waveform of the k-cycle of the level change of the high-frequency power (the voltage change period Tz) Since the number ns of detected data is a function of the control period Tc and the power change period Tz, the value of the control period satisfying the equation n x Tc = ns x Tc is the value of the value of the power change period Tz It changes according to the change. Therefore, in order to reduce the error between the moving average value and the true average value, it is necessary to set the value of the control period Tc to an appropriate value according to the value of the power variation period Tz. In addition, the control period Tc affects the control characteristic of the output control for maintaining the average value of the output of the high-frequency power generating unit at the set value, and sets the value of the control period Tc to a value within an allowable range of the output control There is a need.

Therefore, in a preferred aspect of the present invention, the control period setting means sets the range in which the error occurring between the moving average value of the high frequency power calculated using the n detection data and the true average value of the high frequency power can be kept within an allowable range And the time required for obtaining the n detection data can be kept lower or equal to the upper limit time allowed in controlling the high frequency power generating section.

In another aspect of the present invention, the control period setting means sets an appropriate value of the control period in accordance with the power change period detected by the power change period detecting section, and the high frequency power detecting section detects the latest n detection The time (n x Tc) required to obtain the data is set at a time when an error occurring between the moving average value of the high frequency power calculated using the n detection data and the true average value of the high frequency power can be maintained within an allowable range do.

T(=Tc×｜n-ns｜)를 n 검출 데이터를 사용하여 계산된 고주파 전력의 이동 중간값과 고주파 전력의 참 중간값 사이에서 발생하는 오류가 허용가능한 범위 내에 유지될 수 있는 범위에서의 시간차로 설정한다.In another aspect of the present invention, the control period setting means sets an appropriate value of the control period so that the high frequency power detecting section calculates the time (n x Tc) required to obtain the latest n detection data used for calculating the moving average value Frequency power using detection data obtained by detecting the level of the high-frequency power whose level changes in the power transition period Tz (where m 占 z T Tc and m is an integer of 1 or more) in each control period Tc The time difference (ns x Tc) required to obtain the ns detection data necessary for calculating the arithmetic average value of the level change of the cycle (k is an integer of 1 or more)

In a range where an error occurring between the moving intermediate value of the high frequency power calculated using the n detection data and the true intermediate value of the high frequency power can be maintained within an allowable range, T (= Tc 占 n n-ns | Time difference is set.

T(=Tc×｜n-ns｜)를 허용가능한 범위 내에서 유지한다.In another aspect of the present invention, the control period setting means sets an appropriate value of the control period so that the high frequency power detecting section calculates the time (n x Tc) required to obtain the latest n detection data used for calculating the moving average value (K is an integer of 1 or more) of the high frequency power using the detection data obtained by detecting the level of the high frequency power whose level changes in the power change period Tz (here, Tz? Tc) in each control period Tc, (Ns x Tc) required to obtain the ns detection data necessary for calculating the arithmetic mean value of the level change of the level difference

T (= Tc x | n-ns |) within an allowable range.

T(=Tc×｜n-ns｜)를 최소화한다.In another aspect of the present invention, the control period setting means sets an appropriate value of the control period so that the high frequency power detecting section calculates the time (n x Tc) required to obtain the latest n detection data used for calculating the moving average value (K is an integer of 1 or more) of the high frequency power using the detection data obtained by detecting the level of the high frequency power whose level changes in the power change period Tz (here, Tz? Tc) in each control period Tc, (Ns x Tc) required to obtain the ns detection data necessary for calculating the arithmetic mean value of the level change of the level difference

T (= Tc x | n-ns |).

The error between the moving average value and the true average value of the high frequency power detected by the high frequency power detecting section is reduced when the control period setting means is configured and the appropriate value of the control period is set in accordance with the power variation period as described above according to the individual aspect . Therefore, the moving average value of the high-frequency power is shifted to the upper or lower side of the true average value, and the accuracy of the output control is changed by the fluctuation occurring in the output of the high- It is prevented from deteriorating due to an increase in error occurring between the average value and the true average value.

According to another aspect of the present invention, the control period setting means is configured to calculate an appropriate value of the control period using a map given to the relationship between the detected power change period and the control period.

According to another aspect of the present invention, the control period setting unit is configured to set an appropriate value of the control period within a range of values that can be taken by the control period in the output control of the high-frequency power generating unit.

According to another aspect of the present invention, when the appropriate value of the control period does not exist in the range of the value that can be taken by the control period, the control period setting means sets the value of the value that can be taken by the control period And is configured to change the control period within the range.

When the control period is changed within the set range as time elapses and the appropriate value of the control period does not exist in the set range as described above, the n-detection data used by the high-frequency detection unit to calculate the moving intermediate value is the high- It is possible to prevent the n-detection data from being composed of a group of data obtained by detecting only the levels of the level change waveform of the k cycles of the power, Lt; / RTI > Therefore, errors between the moving average value and the true average value detected by the high-frequency power detecting unit can be reduced.

According to another aspect of the present invention, the number of data ns necessary for calculating the arithmetic mean value of the level change of the k-cycle (k is an integer of 1 or more) of high-frequency power is given by the equation ns = k x Tz / -Tc |}, where m is an integer equal to or greater than 1 and mTz? Tc.

As described above, according to the present invention, the period of the level change occurring in the high-frequency power detected at the output terminal of the high-frequency power generating unit that outputs the high-frequency power of the continuous waveform is the periodic level of the high- And the appropriate value of the control period is set in accordance with the detected power change period. Therefore, in order to prevent occurrence of alternating repetition of a state in which the moving average value detected by the high-frequency power detecting unit performing the output control is shifted toward the upper side of the true average value and a state in which the moving average value is shifted toward the lower side of the true average value, So that fluctuations can be prevented from occurring in the output of the high-frequency power generating apparatus that outputs the high-frequency power having the continuous waveform. Furthermore, according to the present invention, since the control period can be set to reduce the error between the moving average value and the true average value detected by the high-frequency power detecting section, the deterioration of the accuracy of the output control is prevented.

1 is a block diagram schematically showing a configuration of a high-frequency power supply apparatus according to an embodiment of the present invention.
2 is a block diagram showing a state in which a simulated signal is input to simulate a state in which another high-frequency power supply apparatus affects the high-frequency power supply apparatus shown in Fig.
3 is a circuit diagram showing a configuration example of a DC power supply unit provided in the high-frequency power generation unit of the high-frequency power supply apparatus shown in FIG.
4 is a waveform diagram used for explaining a fluctuation phenomenon occurring in an average value of an output when the level change of the output of another high frequency power supply device affects the high frequency power supply device.
5A to 5C are diagrams for explaining a method for simulating a state in which a level change of a pulse-modulated high-frequency power given to a load from another power supply apparatus affects a high-frequency power supply apparatus, Is a graph showing the change in the output level observed when a simulated signal having a different frequency is input.
6A to 6C are diagrams for explaining a method for simulating a state in which a level change of a pulse-modulated high-frequency power given to a load from another power supply apparatus affects a high-frequency power supply apparatus, according to an embodiment of the present invention, A graph showing the change in the output level observed when a simulated signal having a different frequency is input to the output side of the power supply device.
7 is a block diagram showing a state in which two high-frequency power supply devices having two different output frequencies and voltage waveforms supply high-frequency power to the plasma load.
8A is a waveform diagram schematically showing an example of a non-modulated waveform of high-frequency power output from a high-frequency power supply device to be controlled. FIG. 8B is an example of a modulated waveform of high-frequency power applied to a load in the high- As shown in FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

1 is a block diagram schematically showing a configuration of a high-frequency power supply apparatus according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a commercial power supply, reference numeral 2 denotes a DC power supply which is switched to an output DC output of the commercial power supply 1 and whose output level is variable, and reference numeral 3 denotes a power supply voltage from the DC power supply 2 Frequency power amplifier for amplifying a high-frequency signal having the same frequency as the frequency of the high-frequency power supplied to the load using the obtained DC voltage, and outputting a high-frequency signal. The DC power supply unit 2 and the high frequency power amplification unit 3 constitute a high frequency power generation unit 4 that generates high frequency power to be supplied to the load.

The DC power supply 2 includes a rectifying circuit 201 for rectifying the AC voltage obtained from the commercial power supply 1, an inverter 202 for converting the output of the rectifying circuit 201 to an AC output, And a rectifying and smoothing circuit (203) for rectifying and smoothing the output of the rectifying circuit (202).

3, the inverter 202 includes semiconductor switch elements Su and Sv having one end connected in common to be on / off controlled, and a semiconductor switching element Su and Sv connected in reverse parallel connection to the switch elements Su and Sv. And switch elements Sx and Sy each having an upper stage connected to the other end connected to the other end of each of the switch elements Su and Sv and another end connected in common to the upper stage composed of the return diodes Du and Dv, A full bridge type switch circuit having a lower state of a bridge composed of a return diode Dx and Dy connected in antiparallel with the switch elements Sx and Sy and a connection point between the switch elements Su and Sx, And an output transformer TR having a primary coil connected between the AC output terminals 2u and 2v of the switch circuit derived from the connection point of the switches Sv and Sy. In the illustrated inverter, the input terminals 2a and 2b are derived from the common connection point of the switch elements Su and Sv and the common connection point of the switch elements Sx and Sy, and the Dc voltage Vdc ) Are input between the input terminals.

The inverter 202 shown in Fig. 3 alternately turns on the switch elements Su and Sy and the switch elements Sv and Sx in the diagonal positions to convert the DC voltage Vdc to the AC voltage. Off of the switch elements Su and Sv constituting the upper end of the bridge of the same inverter and the switch elements Sx and Sy constituting the lower end of the bridge at a predetermined duty ratio so that the output of the inverter 202 becomes the PWM Respectively. By varying the duty ratio of this PWM control as the operation amount, the output of the inverter 202 can be appropriately changed.

3, the rectifying and smoothing circuit 203 includes a rectifier Rec that rectifies the AC output of the inverter obtained from the second side of the converter TR and a rectifier Rec that rectifies the AC output of the inverter Tr through the choke coil Lc, A smoothing capacitor Cs connected between the output terminals of the smoothing capacitor Cs and a DC voltage Vdc at both ends of the smoothing capacitor Cs.

The high-frequency power amplifier 3 is composed of an amplifying circuit having a power MOSFET or a bipolar power transistor as an amplifying element. The high-frequency power amplifying unit 3 amplifies a high-frequency signal obtained from a high-frequency signal supply source (not shown) that generates a high-frequency signal having the same frequency as the high-frequency power supplied to the load, and outputs high-frequency power having a predetermined frequency. In this embodiment, the high-frequency power amplifying section 3 changes the duty ratio of the PWM control of the inverter 202 as the operation amount and changes the output voltage of the DC power supply section 2 (the high- Power supply voltage) to change the output value of the high-frequency power output from the high-frequency power generation section 4. [

The high-frequency power output from the high-frequency power generating section 4 includes a low-pass filter (not shown), a directional coupler 5, an impedance matching section 6, and a characteristic impedance of 50 that pass only the fundamental frequency component of high- And is supplied to a load 7 such as a plasma load through a transmission line. The directional coupler 5 is reflected by the load 7 and a portion Pf 'of the progressive wave power supplied from the high frequency power generating portion 4 to the load 7 when the impedance matching portion does not completely take the impedance matching And a part Pr 'of the returned reflected wave power is branched and outputted.

The control unit 8 is provided to control the output of the high-frequency power generating unit 4. [ The illustrated control unit 8 includes a timing control unit 801 for controlling the timing and the timing of performing the detection operation by the high frequency power detection unit 801, the duty ratio calculation unit (operation amount calculation unit) 802, the control signal output unit 803, and the high frequency power detection unit 801 And a timing controller 804 for controlling the timing at which the signal output unit 803 outputs the control signal.

The high-frequency power detection unit 801 detects the level of the high-frequency power to be detected from the output of the directional coupler 5 at the output side of the high-frequency power generation unit 4 at the detection timing that is the timing to come in each setting control period , A moving average value calculated from n detection data detected at the latest n (n is an integer of 2 or more) detection timing including the detection timing that comes as such as the average value of the high frequency power to be detected is obtained, and the high frequency power The average value of the high-frequency power to be controlled is detected. The number (n) of detection data used by the high-frequency power detection unit 801 to calculate the moving average value is an integer of 2 or more, and this number is set as an appropriate value by first considering the control characteristics of the output control. In the case of obtaining the detection data in each control period Tc, the time of n x Tc is necessary to obtain the predetermined number (n) of detection data.

The duty ratio calculation unit (operation amount calculation unit) 802 sets the magnitude of a variable for determining the level of the high frequency power output from the high frequency power generation unit as the operation amount of the high frequency power generation unit, and is detected by the high frequency power detection unit And calculates an operation amount necessary to maintain the average value of the high-frequency power to be controlled as the set value.

The control signal output section 803 outputs the control signal given to the high frequency electric power generation section in each setting control period and controls the operation amount of the high frequency electric power generation section 4 as the operation amount calculated by the operation amount calculation section 802 Lt; / RTI >

The operation amount of the high-frequency power generation unit 4 may be variable or variable rate that determines the magnitude of the high-frequency power output from the high-frequency power generation unit 4. [ In the case where the high-frequency power generation section 4 is constituted by the DC power supply section 2 and the high-frequency power amplification section 3, the variable rate which determines the output of the high-frequency DC power supply section and the gain of the high- It can be regarded as an operation amount of the power generation unit. For example, in this embodiment, the DC power supply 2 includes a rectifying circuit 201 for rectifying the AC output of the commercial power supply to a DC output, an inverter 202 for converting the output of the rectifying circuit 201 to an AC output, And a rectifying and smoothing circuit 203 for rectifying and smoothing the output of the inverter 202. The DC output voltage is adjusted through PWM control of the inverter 202 to adjust the output of the high frequency power amplifier 3 The duty ratio of the PWM control can be regarded as the operation amount of the high frequency electric power generating section 4. [

In this case, the operation amount calculation unit 802 calculates the duty ratio of the PWM control of the inverter necessary for maintaining the average value of the high-frequency electric power detected by the high-frequency electric power detection unit 801 as a control target at the set value as the operation amount And the control signal output section 803 outputs a control signal given to the inverter 202 (signal for turning on / off the switching elements constituting the inverter) to perform the PWM control of the inverter 202 at the calculated duty ratio, Period.

In this embodiment, the duty ratio of the PWM control of the inverter 202 for determining the output voltage of the DC power supply 2 is considered as the operation amount of the high-frequency power generating portion, and the reflected wave power Pr from the traveling wave power Pf The obtained effective power is regarded as the high-frequency power to be controlled. Therefore, the high frequency detection unit 801 sets both the reflected wave power Pr and the traveling wave power Pf to be detected, detects the moving average value of the individual power in each control period, and calculates the moving average value of the traveling wave Pf from the moving average value of the traveling wave Pf The moving average value of the active power to be controlled is obtained through subtraction of the moving average value of the reflected wave power.

The control signal output unit 803 outputs the switch elements Su and Sv at the upper end of the bridge of the inverter 202 in order to perform PWM control of the output of the inverter 202 of the DC power supply unit 2 with the calculated duty amount, And a control terminal for interrupting the output of the inverter 202 with the duty ratio calculated at the control terminal of the switch elements Sx and Sy at the bottom of the bridge of the inverter. Therefore, through adjustment of the output voltage of the DC power supply 2, the high-frequency power having the same average value of the set values is output from the high-frequency power amplifier 3.

When the traveling wave power Pf given to the load from the high-frequency power generating unit 4 is to be controlled, the high-frequency power detecting unit 801 does not need to detect the reflected wave power Pr.

The timing controller 804 controls the timing at which the high-frequency power detection unit 801 performs the detection operation and the timing at which the control signal output unit 803 outputs the control signal.

7, the inverter is provided with a first high-frequency power supply device A and a second high-frequency power supply device B, and supplies electric power for simultaneously supplying power to the plasma load C in the high-frequency power supply device Perform various analyzes according to the supply system to specify the following.

(a) When a high-frequency power of a continuous waveform having a substantially constant average value is supplied from the first high-frequency power supply A to the load C, a high frequency power whose level changes periodically due to modulation of high- If the power is supplied to the load C from the second high frequency power supply B, due to the periodic variation of the progressive wave power and the level of the high frequency power given to the load C in the second high frequency power supply B, A periodic level change occurs in the reflected wave power detected by the high-frequency power detection unit of the one high-frequency power supply device A.

(b) the difference between the control period of the output control of the first high-frequency power supply device (A) and the period of the level change is a simple difference, and the average value of the high- (Arithmetic mean value) of the level change of one cycle of the high-frequency power detected from the output side of the first high-frequency power supply device A is calculated from the detection data obtained by detecting the level of the high- The number of detection data ns necessary for accurate calculation is much higher than the number of detection data (n; n is predetermined) used for calculating the moving average value in the high-frequency power detection unit of the first high-frequency power supply A Only the detection data for a part of the waveform of one period of the level change of the high-frequency power is used to calculate the moving average value through the corresponding high- May be included in the n-detection data used. A state in which the moving average value of the high frequency power detected by the high frequency power detecting unit in each control period is shifted upward of the true average value and a state in which the moving average value is shifted downward from the true average value is repeated at a low frequency.

(c) As described above, in each control period, a state in which the moving average value of the high-frequency power detected by the high-frequency power detecting unit of the first high-frequency power supply unit A is shifted upward of the true average value and a state in which the moving average value is shifted downward When the state is repeated at a low frequency, the level change (fluctuation) of the low frequency occurs at the average value of the output of the high frequency electric power generating section of the first high frequency electric power supplying device (A).

(d) As described above, the modulated frequency of the high-frequency power supplied to the load C by the second high-frequency power supply device B changes and is detected at the output side of the high- The error between the moving average value of the high-frequency power detected by the high-frequency power detecting unit of the first high-frequency power supply device A becomes large, and the accuracy of the output control may deteriorate.

As a result of carrying out various experiments based on the above-described matters, the inventor has found that the control period can be appropriately changed in accordance with the change in the first high frequency power of the first high frequency power supply device A The difference between the control period and the power variation period can be set to an appropriate value, if it is set to an appropriate value according to the period of the periodic level change (power variation period) of the high-frequency power detected from the output side of the power generation unit, Frequency power detected by the high-frequency power detecting unit is changed such that the moving average value of the high-frequency power detected by the high-frequency power detecting unit is shifted upward or downward from the true average value, It has been found that the error increases and the accuracy of the output control is prevented from deteriorating.

In the power supply system shown in Fig. 7, the high-frequency power of the non-modulated continuous voltage waveform whose average value is constant as shown in Fig. 8A and the high-frequency power of the pulse modulation voltage waveform from the second high- Is supplied at the same time to the plasma load c supplied as shown in Fig. In this case, as shown in FIG. 8B, the high-frequency voltage applied to the load C in the second high-frequency power supply B has alternating waveforms of "high" period and "low" period, Quot; high "period and the" low "period are different from each other. When the pulse-modulated high-frequency power is supplied to the load C such as a plasma load, the impedance of the load C is periodically changed in accordance with the level change of the modulated high-frequency power. As a result, the impedance of the load appearing at the output terminal of the high-frequency power supply device A that generates the non-modulated high-frequency power having a constant average changes periodically, and the progressive wave power Pf detected at the output terminal of the high- And the level of the reflected wave power Pr periodically change to an average value or more. In this case, in particular, the reflected wave power Pr shows a considerable level variation.

If the high-frequency power given to the plasma load C from the second high-frequency power supply B is modulated by the pulse waveform, it is applied to the load C from the second high-frequency power supply B as shown in Fig. The high-frequency voltage V2 becomes a waveform in which the envelope forms a rectangle. However, due to the reaction delay, the waveform of the envelope of the actual high-frequency voltage does not become a complete rectangle but becomes a waveform close to a sine waveform. Under this influence, the changed waveform of the voltage level V1 of the reflected wave power Pr and the traveling wave power Pf detected at the output terminal of the high frequency electric power generating section 4 of the first high frequency electric power supplying apparatus A is converted into a sinusoidal waveform It becomes a near waveform. Therefore, in this embodiment, due to the influence of the modulated high-frequency power given to the load C in the other high-frequency power supply device B, the reflected wave power Pr and the traveling wave (Pr) detected at the output terminal of the high- Pf) changes in the form of a sinusoidal waveform rising and falling over the true average value (Po).

As described above, the high-frequency power detecting section 801 detects the level of the high-frequency power to be detected at each detection timing that comes in the set control period Tc, and calculates the n (n is an integer of 2 or more ) The moving average value is obtained from the detection data and the moving average value is detected as the average value of the high frequency power to be detected.

The high-frequency power detecting unit 801 used in this embodiment is configured to subtract the average value of the reflected wave power Pr from the detected value of the detected traveling wave power Pf as described above to determine the validity of the high- Calculates a mean value of the power, and provides a calculated average value of the effective power to the duty ratio calculation section 802. [

The duty ratio calculation unit 802 calculates the duty ratio of the PWM control of the inverter 202 of the high frequency power generation unit 4 as the operation amount and controls the high frequency power detection unit 801 The deviation between the average value of the high-frequency power detected by the high-frequency power detector and the power setting value becomes zero. The control signal output section 803 provides a control signal to the high frequency power generation section 4 in each control period Tc so that the operation amount of the high frequency power generation section 4 is calculated by the duty ratio calculation section 802 . Therefore, the duty amount calculation section 802 calculates the duty value of the output value of the high frequency power (the effective power obtained by subtracting the reflected wave power Pr from the progressive wave power Pf in this example) And a mean value of a plurality of instantaneous values to be detected).

The inventor has connected the pseudo signal generator 30 to an output port for outputting the progressive wave power Pf 'of the directional coupler 5 and a port for outputting the reflected wave power Pr' A pseudo signal of a sinusoidal waveform having a frequency equal to the frequency of the pulse modulated waveform of the high frequency power given to the load C from the other high frequency power supply B is supplied to the progressive wave power Pf 'and the reflected wave power Pr' An experiment was performed to superimpose the pulses and to simulate a state in which the pulse-modulated high-frequency power is supplied from the other high-frequency power supply device B to the load. In this experiment, if there is a slight difference between the control period Tc and the power level change period Tz as a result of various tests through fine changes of the control period, the variation in the average value of the output of the high- It became clear that it happened. Hereinafter, the test results will be described in detail.

4, the level of the high-frequency power (in this embodiment, the progressive wave power Pf 'and the reflected wave power Pr') to be detected is detected at each detection timing that comes every time the control period Tc elapses And the average value (moving average value) of the latest n (n is an integer of 2 or more) detection timing including the latest detected data is detected as an average value of the high frequency power to be detected. In addition, generally, the detected data detected at the individual detection timing becomes the latest detected data, and the number (n) of detection data used to calculate the moving average value and the number (k) Is set to be sufficiently large, the detection data detected at the immediately preceding detection timing may be, for example, the latest detection data.

Px(=Px-Po, x=1, 2, 3,..., 및 n)는 검출 수가 반복될 때마다 평균값의 위쪽을 향해 치우치도록 조금씩 변한다. 이러한 경우에, 1 사이클의 레벨 변화를 감지하기 위해 필요한 검출 데이터의 수(ns)가 상당히 커지므로, 즉, ns>>n이므로, 레벨 변화된 고주파 전력의 평균값을 정확하게 계산하는데 필요한 검출 데이터는 고주파 전력의 이동 평균값을 계산하는데 사용되는 n 검출 데이터에 포함되지 않는다.Here, as shown in Fig. 4, the control period Tc is a period of change (Tz) of the power level (the difference between Tc and Tz is a slight difference) in the same period as the period T3 of the modulated signal of the above described frequency f3 4, the detection timing is slightly shifted to the right every time the detection number is repeated, so that the level Px of the high-frequency power detected by the high-frequency power detection section 801 at each detection timing is set to be slightly longer than the level And the average value (Po)

Px (= Px-Po, x = 1, 2, 3, ..., and n) slightly changes so that the detection number is shifted toward the upper side of the average value each time it is repeated. In this case, since the number of detection data ns necessary for sensing the level change of one cycle is considerably large, that is, ns > n, the detection data necessary for accurately calculating the average value of the level- Is not included in the n-detection data used to calculate the moving average value of the motion vector.

4, the moving average value of the high-frequency power is given as (P1 + P2 + ... + Pn), and the detected data P1, P2 .... are shifted to the upper side of the true average value Po , The calculated moving average value Po 'is larger than the average value Po. The value of the moving average value Po 'may also change with the lapse of time since the step of obtaining the n-detection data used for calculating the moving average value is gradually shifted in the right direction in Fig. 4 as time elapses. When the value is changed to a specific point, the moving average value Po 'represents a value that deviates from the lower side of the true average value Po.

On the other hand, when the control period Tc is somewhat shorter than the power level change period Tz, the difference between the level Px and the average value Po of the high-frequency power detected by the high-frequency power detection unit 801 at each detection timing is And changes to be shifted to the lower side of the average value Po every time the detection number is repeated. In this case, the detected mean value Po 'of the high-frequency power shows a value smaller than the true average value Po. Even in this case, the actually detected average value Po 'gradually increases or decreases in accordance with the change in the phase relationship of the high-frequency power to be detected and the detection timing.

As described above, if the difference between the control period Tc and the power change period Tz is small, then the calculated value of the moving average value Po 'gradually increases and varies around the true average value Po so that the moving average value Po '), The output of the high-frequency power generating unit 4 is gradually changed so as to induce a fluctuation in the output.

In addition, in the case of detecting the number of detection data (n) used for calculating the moving average value and the level of the high-frequency power whose level is changed in the power variation period Tz in each control period, in order to obtain the arithmetic average value of the high- The error between the moving average value and the true average value Po becomes large and the accuracy of the output control for maintaining the average value of the output of the high frequency electric power generating section 4 at the set value becomes large if the difference from the number of data used (ns) Lt; / RTI > Generally, the same problem arises when the difference between the control period Tc and m 占 z z (m is an integer of 1 or more) is small. Therefore, it is necessary to avoid that the difference between the control period Tc and the power change period m 占 z z becomes a slight state.

If the control period Tc is equal to the change period Tz or Tc = m 占 T z, the moving average value Po 'of the level of the high frequency power detected by the high frequency power detection unit 801 in each control period Tc is approximately And does not cause any fluctuation in the output of the high-frequency power generating section 4. [ However, in this case, if the level detected at an arbitrary detection timing has an error related to the true average value Po, detection data including the same error at the next detection timing is obtained. Therefore, the calculated moving average value also includes an error, and if this error is large, the control accuracy of the output of the high-frequency power generating unit 4 is lowered. Therefore, it is necessary to avoid setting Tc = m 占 T z.

According to the present invention, in order to prevent the above-described problem from occurring, the control period Tc is appropriately changed in a range that does not affect the control (the range in which the stability of the control is not hurt), and the control period Tc is the high- (Power change period Tz) of the high-frequency power detected at the output side of the power supply section 4 is set to an appropriate value. Although the moving average value Po 'of the high frequency power detected by the high frequency power detecting unit 801 in each control period is not true even though the true average value Po of the high frequency power detected at the output terminal of the high frequency power generating unit 4 is constant, It is possible to prevent a phenomenon showing a shift that deviates upward or downward from the mean value Po, so that the high-frequency power generator 801 is prevented from fluctuating in the output.

As a result, in this embodiment, as the power change period Tz, the high frequency electric power Pf 'from the reflected wave power Pr' detected at the output side of the high frequency electric power generating section 4 and / It is possible to detect the period of the level change of the reflected wave power and / or traveling wave power detected at the output side of the high frequency electric power generating section 4 due to the periodic change of the level of the high frequency electric power given to the load C in the device B A control period setting means 11 for setting a control period Tc to an appropriate value in accordance with the power variation period Tz detected by the power variation period detection unit 10 is provided. The timing controller 804 controls the timing at which the high frequency power detection unit 801 detects the high frequency power and the timing at which the high frequency power is detected at the control signal output unit 803 in order to set the control period Tc in the period set by the control period setting unit 11 And controls the timing at which the control signal is given to the high-frequency power generating section 4. [

In addition, one of the reflected wave power Pr and the traveling wave power Pf detected at the output terminal of the high-frequency power supply device A is the reflected wave power Pr which is heavily influenced by a change in the impedance of the load. Due to this, it is preferable that the power variation period detection unit 10 is configured to detect the period Tz of the level variation based on the reflected wave power Pr 'detected mainly through the directional coupler 5.

In this embodiment, the high-frequency power generation unit 4, the directional coupler 5, the control unit 8, the power variation period detection unit 10, and the control period setting unit 11 constitute a high-frequency power supply unit.

If the value of the control period Tc is set to an appropriate value for the power change period Tz as described above, a value shifted to the higher side of the true average value is determined as a state represented by the detected moving average value, The value of the control period can be set in order to prevent the repetition of the shifting state from occurring, and it is possible to prevent the fluctuation in the output of the high-frequency power generating device 4 that outputs the high-frequency power having the continuous waveform (non-modulated waveform) . In addition, since the control period Tc can be set to reduce the error between the moving average value Po 'and the true average value Po, the deterioration of the accuracy of the output control can be prevented.

As described above, if the difference between the control period Tc and the power variation period Tz is small, the difference between the moving average value and the true average value detected by the high frequency power detection unit 801 becomes large, It changes slowly and fluctuates and causes fluctuations in the output. However, if the difference between the control period Tc and the power transition period Tx is set somewhat larger, then the moving average value can be calculated in the form of near the true average value.

As an example, it can be considered that one period of the power variation period Tz is represented by 0 to 100% and the control period Tc is extended by 10% with respect to the power variation period Tz. In this case, the level P1 detected in the first control period is a level detected when the specific power transition period Tz is exceeded by 10% (the end time of the first control period Tc). In addition, the level P1 detected in the second control period is a level detected when the next power change period Tz is exceeded by 20%. Therefore, in the same manner, the levels P3, ..., P8, P9 and P10 are detected when the power variation period Tz is exceeded by 30%, ..., 80%, 90% and 100%, respectively. In this case, since the moving average value of the power calculated at each detection timing can take an upper or lower value with respect to the true average value Po, a state in which the detected moving average value gradually changes around the true average value Po does not occur . In this case, if the level Px of the high-frequency power is detected ten times, since the level Px is detected over the entire region of the power variation period Tz, the moving average value of the high- (Po).

Conversely, when the control period Tc is shortened by 10% with respect to the power variation period Tz, the level P1 detected in the first control period is detected when the specific power variation period Tz exceeds 90% . In addition, the level P2 detected in the second control period is a level detected when the next power change period Tz is exceeded by 80%. Thereafter, in the same manner, the level Px is detected when the power variation period Tz is exceeded by 70%, ..., 30%, 10% and 0%, respectively. In this case, it does not occur when the detected level rises and falls around the true average value Po in the same manner as when the control period Tc is extended by 10% with respect to the power variation period Tz. Even in such a case, if the level Px of the high-frequency power to be detected is detected ten times, the level Px is detected through the entire region of the power change period Tz, and therefore, the moving average value of the high- (Po).

The moving average value of the high frequency power can be made closer to the true average value by slightly increasing the difference between the control period Tc and the power variation period Tz even when a periodic level change occurs in the high frequency power as described above. Therefore, in order to increase the difference between the control period Tc and the power variation period Tz within the allowable range in performing the output control of the high-frequency power generation section 4, Tc) is set so that fluctuations do not occur in the output of the high frequency electric power generating section 4, and deterioration of the accuracy of the output control is prevented. The appropriate value of the control period Tc can be calculated using a map used to calculate the control period giving the relationship between the appropriate value of the control period Tc and the power change period Tz. This map can be provided based on the results of the experiment.

Further, according to the description hereinafter, the appropriate value of the control period Tc is the number of detection data (n) (predetermined number) used for calculating the moving average value and the number of detection data (n x Tc) required to obtain the n detection data used to calculate the moving average value and the number ns of necessary data (ns) And the time (ns x Tc) required for the operation.

In order to calculate the true average value through the calculated average when the average value of the high frequency power is obtained from the value detected through the detection of the level of the high frequency power at a predetermined time interval when the level of the high frequency power is periodically detected, It is necessary to take an average of detection data obtained by detecting the entire change waveform of the change k (k is an integer of 1 or more) cycle. In order to calculate the moving average value as a value close to the true average value, the n-detection data used for the calculation is the individual portion of the k-cycle waveform of the level change of the high-frequency power to be detected without irregularity even when calculating the moving average value of the high- It is necessary to be data obtained by detecting the level of the data. If the n detection data used to calculate the moving average value includes only detection data of a portion of the waveform of one cycle of the level change waveform, any error occurs between the moving average value and the true average value.

The average value of the high-frequency power is detected through the detection of the level of the high-frequency power in each control period Tc, and when the level is a change in the power variation period Tz, the average value of the k The number of detection data (ns; the number of required data) that need to be obtained for the waveform of the cycle can be calculated by the following equation.

Ns = {Tz / | m? Tz-Tc |} (1)

Here, m is an integer of 1 or more, and the following relationship is assumed to be established between Tz and Tc.

mTz? Tc (2)

In addition, if the result of the calculation of equation (1) is not an integer, appropriate fractional processing such as rounding, close, and cutoff is performed.

In equation (1), if the difference between Tc and m 占 z z is a simple difference, then the denominator power variation period Tz is multiplied by m, which is why the same problem can generally occur.

In calculating the moving average value of the high-frequency power through detection of the level of the high-frequency power varying in the power variation period Tz in each control period Tc, Equation 1 is used to reduce the error between the moving average value and the true average value. It is preferable that the number ns of the necessary data calculated by the moving average value coincides with the number n of detection data used for calculating the moving average value (n = ns) or a difference between n and ns. Furthermore, since the time required to calculate the moving average value is n x Tc and the time required to obtain ns detection data is ns x Tc, the control period is set so that the equation of n x Tc = ns x Tc is satisfied, or n x Tc And ns x Tc so that the error between the moving average value and the true average value is reduced.

the data obtained by detecting the level information of the waveform in one cycle of the level change of the high frequency power without irregularity can be included in the n detection data used for the moving average value if ns > ns (ns x Tc > n x Tc) The error between the moving average value and the true average value becomes large. In addition, if ns < n (ns x Tc < n x Tc) is satisfied, the data unnecessary for accurately calculating the average value of the high frequency power is data included in the n detection data used for the moving average value. Thus, in the same way, the error between the moving average value and the true average value becomes large.

As can be clearly seen in Equation (1), the number of necessary data to be obtained for one cycle of the waveform of the level change of the high-frequency power (in the voltage variation period Tz) in order to accurately calculate the average value of the high- ns is a function of the control period Tc and the power change period Tz so that the value of the control period that satisfies the equation n x Tc = ns x Tc varies with the change of the value of the powering period Tz. Therefore, in order to reduce the error between the moving average value and the true average value, it is necessary to set the value of the control period Tc to an appropriate value according to the value of the power variation period Tz. In addition, the control period Tc influences the control characteristic of the output control so that the average value of the output of the high-frequency power generation unit is maintained at the set value, so that the value of the control period Tc is set to a value within the allowable range of the output control Need to be.

In the above description, the control period setting means 11 may be configured to set the control period Tc by the following thinking method.

(A) The control period setting means may set the value of the control period to a range in which an error occurring between the moving average value of the high frequency power calculated using the n detection data and the true average value of the high frequency power is allowable, The time required for obtaining the data is set to an appropriate value which is a value in a range in which the time to obtain the data can be kept lower than or equal to the upper limit time allowed for controlling the high frequency power generating section.

(B) The control period setting means sets an appropriate value of the control period in accordance with the power change period detected by the power change period detecting unit, and sets the control period to be the time required to obtain the latest n detection data used for calculating the moving average value n x Tc) is set to a time which allows an error occurring between the moving average value of the high frequency power calculated using the n detection data and the true average value of the high frequency power to be kept within an allowable range.

T(=Tc×｜n-ns｜)를 n 검출 데이터를 사용하여 계산되는 고주파 전력의 이동 평균값과 고주파 전력의 참 평균값 사이에서 일어나는 오류가 허용가능한 범위 내에 유지되는 범위의 시간차로 설정한다.(C) the control period setting means sets the appropriate value of the control period, and the time (n x Tc) necessary for obtaining the latest n detection data used by the high frequency power detecting section to calculate the moving average value, and , An arithmetic average value of the level change of k (k is an integer of 1 or more) cycle of the high-frequency power using the detection data obtained by detecting the level of the high-frequency power whose level changes in the power change period Tz Time difference (ns x Tc) required to obtain the ns detection data required for calculation

T (= Tc 占 n n-ns |) is set to a time difference within a range in which an error occurring between the moving average value of the high frequency power calculated using the n detection data and the true average value of the high frequency power is within an allowable range.

T(=Tc×｜n-ns｜)를 허용가능한 범위에 유지한다.(D) the control period setting means sets the appropriate value of the control period, the time (n x Tc) necessary for obtaining the latest n detection data used by the high frequency power detecting section to calculate the moving average value, Calculating an arithmetic average value of the level change of k (k is an integer of 1 or more) cycle of the high-frequency power using the detection data obtained by detecting the level of the high-frequency power whose level changes in the power change period Tz (here, Tz? Tc) (Ns x Tc) required to obtain the ns detection data necessary for obtaining the ns detection data

T (= Tc x | n-ns |) in an allowable range.

T(=Tc×｜n-ns｜)를 최소화한다.(E) the control period setting means sets an appropriate value for the control period, and the time (n x Tc) necessary for obtaining the latest n detection data used by the high frequency power detecting section to calculate the moving average value and the time Calculating an arithmetic average value of the level change of k (k is an integer of 1 or more) cycle of the high-frequency power using the detection data obtained by detecting the level of the high-frequency power whose level changes in the power change period Tz (here, Tz? Tc) (Ns x Tc) required to obtain the ns detection data necessary for obtaining the ns detection data

T (= Tc x | n-ns |).

According to these aspects, when the appropriate value of the control period Tc is set according to the power change period Tz, the error between the moving average value and the true average value of the high frequency power detected by the high frequency power detecting unit 801 can be reduced have. Therefore, the moving average value of the detected high-frequency power is changed to be shifted to the higher or lower side of the true average value, so that the fluctuation occurring in the output of the high-frequency power generating section or the error occurring between the moving average value and the true average value detected by the high- The accuracy of the output control is prevented from deteriorating.

(Px)의 시간 간격 값의 절대값을 최소화하는 값으로 설정될 수 있다. 여기서, 차이

Px의 시간 적분 값은 미리 결정된 시간(T) 동안 검출되는 일련의 검출 데이터(P1, P2, ... 및 Pn)와 고주파 전력의 참 평균값(Po) 간의 차이

P1,

P2, ...

Pn의 총 값이다. 고주파 전력의 검출된 레벨(Px)이 참 평균값(Po)보다 높은지, 낮은지의 여부는 차이의 포지티브 마크 또는 네거티브 마크에 의해 결정되는 방식으로 차이가 계산된다.In addition, when the appropriate value of the control period Tc does not affect the level (Px) of the high-frequency power detected by the high-frequency power detection section 801 and the control of the high-frequency power at each detection timing, The difference between the mean values (Po)

May be set to a value that minimizes the absolute value of the time interval value of the time interval Px. Here,

The time integral value of Px is a difference between a series of detection data (P1, P2, ..., and Pn) detected during a predetermined time (T) and a true average value Po of high frequency power

P1,

P2, ...

Pn. &Lt; / RTI &gt; The difference is calculated in such a manner that the detected level Px of the high frequency power is higher or lower than the true average value Po by the positive mark or the negative mark of the difference.

When the control period Tc is set as described above, the moving average value of the high-frequency power detected by the high-frequency power detecting unit 801 is the level change of the high-frequency power supplied to the load C from the other high- And is substantially the same as the true average value Po of the high-frequency power detected at the output terminal of the high-frequency power generating section 4. [ Therefore, in order for the moving average value of the high-frequency power detected by the high-frequency power detecting unit 801 to fluctuate, it is limited to be influenced by the level change of the high-frequency power supplied from the other high-frequency power supply B to the load C do.

It is preferable that the control period setting means 11 is configured to calculate an appropriate value of the control period taking a value in a predetermined range so as not to cause a problem in the control of the high frequency power by using the map to calculate the control period This map gives a relationship between the load change period Tz detected by the power change period detection unit 10 and an appropriate value of the control period Tc. The map for calculating the control period used in this case is a map that measures the change amount of the output of the high frequency power generation section while varying the control period of the output control for the individual modulation frequency of the high frequency power output by the other high frequency power supply device And can be provided based on experimental results.

The state in which the pulse-modulated high-frequency power is supplied to the load from another high-frequency power supply can be simulated by superimposing a pseudo signal having the same frequency as the pulse-modulated waveform with the high-frequency power on the output side of the high- have. 2, the pseudo signal generator 30 is connected to an output port for outputting the progressive wave power Pf 'of the directional coupler 5 and a port for outputting the reflected wave power Pr' A pseudo signal having the same frequency as the frequency of the pulse-modulated waveform of the high-frequency power given to the load from the power supply unit is superposed on the reflected wave power Pr 'detected by the directional coupler 5 and the progressive wave power Pf' .

As an example, the high frequency power of a continuous waveform of 3.2 MHz is supplied to the plasma load C from the pulse-modulated high-frequency power of 60 MHz given in the other high-frequency power supply B, for example. The overlapping of the sinusoidal pseudo signals having the same frequency as the pulse-modulated waveform of the high-frequency power given to the load in the other high-frequency power supply apparatus by the reflected wave power Pr 'and the traveling wave power Pf' output from the bidirectional coupler 5 An experiment was conducted to check the control characteristics through

 When performing pulse modulation of high-frequency power of 60 MHz supplied from the other high-frequency power supply B to the load C to generate plasma at the plasma load C, the frequency of the pulse-modulated waveform is, for example, 90 kHz. In an experiment performed in this case, a pseudo signal having such a frequency is supplied to the pseudo-signal generator 30 (30), assuming that the frequencies of the pulse-modulated waveform of the high-frequency power of 60 MHz given to the load in other high-frequency power supply devices are set to 10 kHz, 40 kHz and 70 kHz And the output of the inverter 202 of the DC power supply unit 2 is PWM-controlled, the duty of the DC power supply unit 2 is increased by 50% The control is performed so as to maintain the level of the high-frequency power output from the high-frequency power generating section 4 at the set value.

In the experiments described above, temporal changes in the output level of the high-frequency power generating section 4, which are measured when the frequencies of the pseudo signals are 10 kHz, 40 kHz, and 70 kHz, are shown in Figs. 5A to 5B. In the figure, the vertical axis represents the power value [W] and the horizontal axis represents the time [msec]. As is clearly shown in the drawing, in a high-frequency power supply in the related art, if the pulse-modulated high-frequency power is supplied to the load from another high-frequency power supply, this is affected by the pulse-modulated waveform and its output level fluctuates at a low frequency .

In the embodiment of the present invention, the same experiment as described above was performed by setting the control period Tc to be sufficiently long according to the power change period Tz of the allowable range of the power level, and the output of the high frequency power generating section 4 The difference between the level (Px (instantaneous value) and the true average value Po of the high-frequency power detected in each control period Tc when the level change of the high-frequency power detected by the high-frequency power detecting section 801 is detected by the high- But did not deviate to the upper or lower side of the average value Po. A temporal change in the output level of the high-frequency power generating section 4 shown when the frequency of the pseudo signal is set to 10 kHz, 40 kHz, and 70 kHz is shown in Figs. 6A to 6C.

As apparent from these results, according to the present invention, even if the high-frequency power modulated by the pulse waveform or the like is supplied to the load from another high-frequency power supply device, the average value of the high-frequency power output from the high- Frequency fluctuation in the average value of the output is prevented from occurring under the influence of the level change of the high-frequency power given to the load C from the other high-frequency power supply device B .

When the appropriate value of the control period Tc does not exist in an allowable range for control, the control period setting means 11 is configured to change the control period Tc within the set range with the lapse of time, The output change due to the change of the output of the high-frequency power supply B can be restricted.

When a proper value of the control period does not exist in the set range, a control period that is changed within the set range with the lapse of time is formed, whereby the phase for detecting the high-frequency power is appropriately changed by the high-frequency power detection unit 801 , The n-detection data used by the high-frequency power detection unit 801 to calculate the moving average value is prevented from being composed of a data group obtained by detecting only the level of a specific portion of the k-cycle level change waveform of the high-frequency power. Therefore, the error between the moving average value and the true average value detected by the high-frequency power detecting section can be reduced.

In the embodiment described above, the control for maintaining the level of the high-frequency power output from the high-frequency power generation section 9 at the set value is performed through the control of the output voltage of the DC power supply section 2. [ However, the control for maintaining the level of the high-frequency power output from the high-frequency power generating section 9 at the set value is performed by controlling the high-frequency power amplifying section 3 while maintaining the output voltage of the DC power supplying section 2 constant Even when the control for maintaining the level of the high-frequency power output from the high-frequency power generating section 9 at the set value is performed in consideration of the benefit of the operation amount high-frequency power amplifying section 3, The invention can be applied. In addition, a high-frequency power generating unit 4 having a DDS (direct digital synthesizer) for generating a high-frequency signal having the same frequency and amplitude as that commanded by the frequency command and amplitude command and an amplifier for amplifying the output of the DDS The output of the high frequency power generating section 4 can be controlled in consideration of the amplitude command given to the DDS as the operation amount.

In the above description, in order to simulate the state in which the high-frequency power having the periodic level change is supplied from the other high-frequency power supply B to the load, an output port for outputting the progressive wave power Pf 'of the directional coupler 5 A pseudo signal is given to both the ports for outputting the reflected wave power Pr '. However, the pseudo signal can be given to any one of an output port for outputting the progressive wave power Pf 'of the directional coupler 5 and a port for outputting the reflected wave power Pr', and for example, the reflected wave power Pr ' It can only be given to the output port.

In the embodiment described above, only the control for maintaining the average value of the high-frequency power (traveling wave power or active power) to be controlled by the control unit 8 at the set value is performed. However, the present invention is not limited to the control for restricting the total value of the traveling wave power and the reflected wave power below an allowable upper limit value for protecting the semiconductor device constituting the power amplifying part, Reduction control for the output of the power supply 2, and the like.

Claims (12)

As a high-frequency power supply device,
A high frequency electric power generating unit configured to output a high frequency electric power to be supplied to the load; And
And a control unit configured to detect an average value of the high frequency power to be controlled at the output side of the high frequency power generation unit and to control the high frequency power generation unit to maintain the detected average value of the high frequency power at a set value,
Wherein,
In order to obtain the high frequency power to be controlled at the timing coming into each control period (Tc) as the detection timing, the detection data of the level of the high frequency power which needs to be the detection target is obtained, And the moving average value is set as an average value of the high-frequency power to be detected, thereby obtaining the high-frequency power to be the object of the control A high frequency electric power detection unit configured to detect an average value of the electric power;
And a control unit that sets a magnitude of a variable for determining the level of the high frequency power output from the high frequency power generation unit as an operation amount of the high frequency power generation unit and sets the average value of the high frequency power detected by the high frequency power detection unit, An operation amount calculation unit configured to calculate the operation amount necessary to maintain the set value; And
And a control signal output unit configured to output a control signal given to the high frequency power generation unit in each control period so as to set the operation amount of the high frequency power generation unit to the operation amount calculated by the operation amount calculation unit,
The high-frequency power supply device includes:
And a power variation period detection unit configured to detect a level variation period of the high frequency power detected at the output side of the high frequency power generation unit due to a periodic change in the high frequency power level given to the load from another high frequency power supply unit as the power variation period Tz, ; And
And a control period setting unit configured to set the control period (Tc) to an appropriate value in accordance with the power variation period (Tz) detected by the power variation period detection unit. The control method according to claim 1, wherein the control period setting unit is configured to allow the error occurring between the moving average value of the high frequency power calculated using the n detection data and the true average value of the high frequency power to be kept within an allowable range, And sets an appropriate value of the control period to a value within a range in which a time required for obtaining data can be maintained to be equal to or lower than an upper limit time allowed in controlling the high-frequency power generating unit. The control method according to claim 1, wherein the control period setting unit sets an appropriate value of the control period in accordance with the power change period detected by the power change period detecting unit and outputs the latest n detection data (N x Tc) required for obtaining the high-frequency power detection section is set to be within a range in which an error generated between a moving average value of the high-frequency power calculated using the n detection data and a true average value of the high- To a time that can be maintained in the high-frequency power supply. The control method according to claim 1, wherein the control period setting unit sets an appropriate value of the control period to calculate the latest n detection data used for calculating the moving average value from the time (n x Tc) required for obtaining the high- And an arithmetic average value of the level change of the k-cycle of the high-frequency power by using the detection data obtained by detecting the level of the high-frequency power whose level changes in the power change period (Tz) in each control period (Tc) (Ns x Tc) required to obtain the ns detection data necessary for obtaining the ns detection data

(Tc = | n-ns |) is set such that an error occurring between a moving average value of the high frequency power calculated using the n detection data and a true average value of the high frequency power can be maintained within an allowable range Wherein k is an integer equal to or greater than 1, m? Tz? Tc, and m is an integer equal to or greater than 1. 5. The method of claim 4, wherein the number (ns) of detection data required for calculating an arithmetic mean value of the level change of the k-cycle of the high-frequency power is calculated by the equation ns = k x Tz / m Tz-Tc | Frequency power supply. The control method according to claim 1, wherein the control period setting unit sets an appropriate value of the control period to calculate the latest n detection data used for calculating the moving average value from the time (n x Tc) required for obtaining the high- And an arithmetic average value of the level change of the k-cycle of the high-frequency power by using the detection data obtained by detecting the level of the high-frequency power whose level changes in the power change period (Tz) in each control period (Tc) (Ns x Tc) required to obtain the ns detection data necessary for obtaining the ns detection data

Wherein T is equal to or greater than 1, m? Tz? Tc, and m is an integer greater than or equal to 1, wherein T (= Tc x | n-ns |) is within an allowable range. 7. The method of claim 6, wherein the number of detection data ns required to calculate an arithmetic mean value of the level change of the k-cycle of the high-frequency power is calculated by the equation ns = k x Tz / m Tz-Tc | Frequency power supply. The control method according to claim 1, wherein the control period setting unit sets an appropriate value of the control period to calculate the latest n detection data used for calculating the moving average value from the time (n x Tc) required for obtaining the high- And an arithmetic average value of the level change of the k-cycle of the high-frequency power by using the detection data obtained by detecting the level of the high-frequency power whose level changes in the power change period (Tz) in each control period (Tc) (Ns x Tc) required to obtain the ns detection data necessary for obtaining the ns detection data

Wherein T is an integer equal to or greater than 1, m? Tz? Tc, and m is an integer equal to or greater than 1, wherein T (= Tc x | n-ns |) is minimized within an allowable range. 9. The method of claim 8, wherein the number of detection data ns required to calculate an arithmetic mean value of the level change of the k-cycle of the high-frequency power is calculated by the equation ns = k x Tz / m Tz-Tc | Frequency power supply. The high-frequency power supply apparatus according to claim 1, wherein the control period setting unit is configured to calculate an appropriate value of the control period using a map that provides a relationship between the detected power change period and the control period. The high-frequency power supply device according to claim 1, wherein the control period setting unit is configured to set an appropriate value of the control period within a range of values that can be taken by the control period during output control of the high-frequency power generating unit. The control method according to claim 1, wherein the control period setting unit sets a range of values that can be taken by the control period as time elapses when an appropriate value of the control period is not within a range of values that can be taken by the control period Wherein the control unit is configured to change the control period within the control period.

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